Biooxidation-thiosulfate leaching of refractory gold concentrate
来源期刊：International Journal of Minerals Metallurgy and Materials2020年第8期
论文作者：He-fei Zhao Hong-ying Yang Lin-lin Tong Qin Zhang Ye Kong
文章页码：1075 - 1082
摘 要：A process of biooxidation followed by thiosulfate leaching of gold from refractory gold concentrate was investigated. Mineralogical studies on the concentrate showed that very fine gold grains（<10 μm） were encapsulated in pyrite and arsenopyrite, while the proportion of monomer gold was only 21%. The gold-bearing sample was identified as a high-sulfur fine-sized wrapped-type refractory gold concentrate.The gold leaching efficiency obtained by direct cyanidation was only 59.86%. After biooxidation pretreatment, the sulfide minerals were almost completely decomposed, 92 wt% of the mineral particles of the biooxidation residue were decreased to <38 μm, and the proportion of monomer gold in the biooxidation residue was over 86%. Meanwhile, the gold content in the biooxidation residue was enriched to 55.60 g/t,and the S, Fe, and As contents were reduced to approximately 19.8 wt%, 6.97 wt%, and 0.13 wt%, respectively. Ammoniacal thiosulfate was used for gold extraction from the biooxidation residue of the refractory gold concentrate. The results showed that the optimal reagent conditions were 0.18 M thiosulfate, 0.02 M copper（II）, 1.0 M ammonia, and 0.24 M sulfite. Under these conditions, a maximum gold leaching efficiency of 85.05% was obtained.
He-fei Zhao1,2，Hong-ying Yang1,2，Lin-lin Tong1,2，Qin Zhang1,2，Ye Kong1,2
1. Key Laboratory for Ecological Metallurgy of Multimetallic Mineral (Ministry of Education), Northeastern University2. School of Metallurgy, Northeastern University
摘 要：A process of biooxidation followed by thiosulfate leaching of gold from refractory gold concentrate was investigated. Mineralogical studies on the concentrate showed that very fine gold grains（<10 μm） were encapsulated in pyrite and arsenopyrite, while the proportion of monomer gold was only 21%. The gold-bearing sample was identified as a high-sulfur fine-sized wrapped-type refractory gold concentrate.The gold leaching efficiency obtained by direct cyanidation was only 59.86%. After biooxidation pretreatment, the sulfide minerals were almost completely decomposed, 92 wt% of the mineral particles of the biooxidation residue were decreased to <38 μm, and the proportion of monomer gold in the biooxidation residue was over 86%. Meanwhile, the gold content in the biooxidation residue was enriched to 55.60 g/t,and the S, Fe, and As contents were reduced to approximately 19.8 wt%, 6.97 wt%, and 0.13 wt%, respectively. Ammoniacal thiosulfate was used for gold extraction from the biooxidation residue of the refractory gold concentrate. The results showed that the optimal reagent conditions were 0.18 M thiosulfate, 0.02 M copper（II）, 1.0 M ammonia, and 0.24 M sulfite. Under these conditions, a maximum gold leaching efficiency of 85.05% was obtained.
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